In the operation of the apparatus of the Smith & Haley U.S. Pat. No. 4,100,034, if excess pressure builds up in the quenching chamber, material may be blown through the material outlet thereby causing contamination and destabilization of the operation. Also, if excess pressures prevail in the quenching vessel, steam enters the shaft furnace through the material discharging therefrom, thereby undesirably cooling material in the shaft furnace and further destabilizing the operation. Reduction of contacting water in the material in the quench vessel in order to reduce the pressures therein undesireably reduces the cooling of the material. Comparable problems may arise in the operation of the Lewandowski, et al. (supra) apparatus.
The object now is to provide a quenching vessel and method wherein the build-up of excessive pressures within the quench vessel are avoided while still maintaining the desired contact of cooling water.
In accordance with the above-objectives, it is now intended to create two voids, one being a gap in the upper portion of the quench chamber above the angle of repose of the surface of the hot material in the upper portion thereof, and a lower one in the down flowing material centrally of the quench chamber, the cooling water being sprayed onto the hot material surfaces at both voids and the resultant steam being withdrawn directly from both voids without raising the pressure of the steam within the hot material itself.
In addition, it is intended now to provide for total control of the quenching process, controlled by the sensed temperature of the quenched material about to leave the quenching vessel, and the pressure in the gap above the hot material in the upper portion of the quenching vessel, which sensed temperatures and pressures control the amount of waters sprayed into the voids and upon the hot material at the voids, and to control the steam pressure prevailing in both voids.